On April 22, 2020, the Federal Circuit "grappled," as the opinion put it, with the equitable doctrine of assignor estoppel in Hologic, Inc. v. Minerva Surgical, Inc.
The case arose in an infringement suit over U.S. Patent Nos. 6,782,183 and 9,095,348. The patents were directed to "procedures and devices for endometrial ablation." Claim 9 of the '183 patent and claim 1 of the '348 patent were considered by the Court to be representative:
'183 patent:
9. A method of detecting a perforation in a uterus, comprising the steps of:
passing an inflation medium into the uterus;
monitoring for the presence of a perforation in the uterus using a pressure sensor;
if no perforation is detected during the monitoring step, permitting ablation of the uterus using an ablation device; and
if a perforation is detected during the monitoring step, preventing ablation of the uterus.
'348 patent:
1. A device for treating a uterus comprising:
an elongate member having a proximal portion and a distal portion, the elongate member comprising
an outer sleeve and an inner sleeve slidably and co-axially disposed within the outer sleeve;
an applicator head coupled to the distal portion, the applicator head defining an interior volume and having a contracted state and an expanded state, the contracted state being configured for transcervical insertion and the expanded state being configured to conform to the shape of the uterus, the applicator head including one or more electrodes for ablating endometrial lining tissue of the uterus;
a handle coupled to the proximal portion of the elongate member, wherein the handle comprises a frame, a proximal grip and a distal grip pivotally attached to one another at a pivot point and operably coupled to the applicator head so that when the proximal grip and the distal grip are moved closer together, the applicator head transitions from the contracted state to the expanded state;
a deflecting mechanism including flexures disposed within the applicator head, the flexures including first and second internal flexures and first and second external flexures, the first and second external flexures being coupled to the outer sleeve and the first and second internal flexures being coupled to the inner sleeve, wherein the deflecting mechanism is configured so that translating the inner sleeve relative to the frame causes the applicator head to transition from the contracted state to the expanded state; and
an indicator mechanism operably coupled to the inner sleeve, the indicator mechanism configured to indicate a dimension of the uterus [emphases added to indicate disputed claim terms not further discussed herein].
The opinion set out the relationships between the parties in this dispute. Inventor Truckai (named on both the '183 and '489 patents) founded Novocept, which developed a system for detecting perforations in a uterus that could cause serious side effects for women undergoing endometrial ablation; the system depends on introducing carbon dioxide into the uterus and monitoring gas escape. It was undisputed that Novocept's ablation product uses the claimed technology, and that inventor Truckai assigned his right to these patents to Novocept. Thereafter, Novocept was acquired by co-plaintiff Cytyc Corp., which was subsequently acquired by co-plaintiff Hologic. Hologic now sells the Novocept system.
Meanwhile, Inventor Truckai founded accused infringer Minerva and developed the accused infringing article, termed the Endometrial Ablation System (EAS). Hologic sued Minerva over sales of the EAS for infringing the '183 and '349 patents. Hologic moved for summary judgment that Minerva was estopped under the doctrine of assignor estoppel for both the '183 and '348 patents, which motion the District Court granted. Assignor estoppel has differences in both philosophy and patent policy than licensee estoppel, which was abolished by the Supreme Court in Lear, Inc. v. Adkins, 395 U.S. 653, 666 (1969). Licensee estoppel, according to the Supreme Court, was against public policy because a licensee of an invalid patent, of all parties, has the most incentive to see such patents invalidated. (Similar considerations motivated the Supreme Court in MedImmune, Inc. v. Genentech, Inc.) Assignor estoppel, on the...
